Electric switch



June 1940- D. G. KIMBALL 2,203,224

ELECTRIC SWITCH Filed April 13, 1959 Fig.2.

I Inventor: Donald 6. Kimball,

b9 yH i Attorneg.

Patented June 4, 1940 PATENT OFFICE ELECTRIC SWITCH Donald G. Kimball, Stratford, Conn, assignor to General Electric Company, a corporation of New York Application April 13, 1939, Serial No. 267,568

13 Claims.

This invention relates to electric switches, and more particularly to electric switches for use with heating devices, for example, electric ranges.

mechanism; Fig. 2 is a sectional view through the interior of the switch along the line 2--2 of Fig. 1 but with the operating handle attached;

" Fig. 3 is a view of the switch similar to the showing of Fig. 1, but with the cover removed to show the interior of the switch; Fig. 4 is a sectional view through the switch along'the line 4--4 of Fig. 1; Fig. 5 is another sectional view through the switch along the line 55 of Fig. 1; and Figs. 6 to 11, inclusive, are diagrammatic showings illustrating one of themes to which the switch may be put, the switch being connected to a twopant heater system.

Referring to the drawing, an electric switch is shown having a base member in formed of insulating material, for example, a phenolic condensation product and filler, and the base member is provided with a recess I I. In the form of the invention shown, the base member is of rectangular configuration but, manifestly may be made in other forms. Along one wall of the base member and projecting from the bottom of the recess H are a plurality of ledges or stepped members l2. The ledges are formed alternately at two different levels, as shown most clearly by Figs. 2, 3 and 4, and the two respective levels are maintained at the same distance from the bottom of the recess across the wholelength of the series of ledges. A series of fixed contact members are mounted on the ledges l2 and, in the form of the inve tion illustrated, six contact members are mounted upon the switch base. However, the number of contact members may be increased or decreased at will depending upon the circuit requirements with which the switch is to be used. In the following description of the manner in which the contact members are mounted upon the ledges, the different levels of the ledges will be indicated as the upper and lower levels. The actual distance of these levels from the bottom of the recess depends upon the overall dimensions of the switch, the thickness of the contact members, the size of the switch operating mechanism, etc. The first contact member I3 is mounted on a ledge strap 21 l2 at the lower" level and is electrically connected to an adjacent contact member I mounted on the adjoining ledge l2 at the upper level by means of a strap IS. The contact member 14 and one end of the strap l5 are held in position by means of a screw I6 tapped into the corresponding ledge l2 formed in the base member, while the contact member l3 and the other end of the strap are mounted'on the base by means of a rivet H, or other suitable fastening means, which passes through the base Hi to the rear surface thereof as shown by Fig. 4. A terminal member I8 is secured to the base by this same rivet 11. By this construction, the terminal member I8 is in electrical connection with the first and second contact members I3 and I4, respectively. The next adjoining contact member IS, in this case the third contact member, is secured to a lower level ledge by means of a rivet 20 and the rivet 20 passes through the base member ill to the rear surface thereof where it is in electrical contact with one end of a connecting The other end of the connecting strap is electrically connected by means of a rivet 22 to another contact member 23, in this case the fifth contact member, which is likewise mounted on one of the ledges at a lower level. This means that the contact members 23 and H! are electrically interconnected. They are likewise electrically connected to a terminal member 24 secured to the rear face of the housing by a screw 25 which holds the strap 2i in engagement with the terminal member. Another contact member 26, in this case the fourth contact member, is mounted on one of the ledges at the upper level by means of a pin 21 tapped into the base member ID. This contact member is electrically connected to a contact member 28, in this case the sixth contact member, by means of a strap 29. A pin holds the one end of the strap and the contact member 28 in position on the base member while the other end of the strap is held in engagement with the contact member 26 by the pin 21. In this manner the contact members 26 and 28 are electrically interconnected and the contact member 26 is provided with an integral extension forming a terminal member 3| for connecting an electric conductor to each of the contact members 26 and 28.

By the construction described, it will be seen that various ones of the contact members are electrically interconnected for connection to, the various terminal members I8, 24 and 3|, and these contact members are engaged by movable contacts in a predetermined sequence in a manner to be described later. By placing the contact members at different levels adjacentone another, a compact switch construction is obtained which would not be possible were the contact members placed in a single plane with wide spacings, such as would be necessary to insure adequate electrical clearances between the various contacts. Each of the contact members is provided with a contacting surface or button 32 for cooperation with movable contacts and the contact button 32 is placed at an end of each of [the contact members which extends into the recess H. As shown most clearly by Fig. 2, the contact buttons 32 are placed on the upper surfaces of the contact members, that is, facing the front of the recess ii, in the case the second, fourth and sixth contact members, whereas in the first, third and fifth ones of the contact members, the contact buttons are placed on the rear of the contact members facing the bottom of the recess.

A plurality of movable contact members are provided to cooperate with the fixed contacts, and comprise a plurality of contact blades formed or" flexible spring material; the movable contact members extend across the recess ill for engagement with the fixed contact members. These movable contact members are similarly placed at different levels corresponding to the levels of the fixed contact members and the bases of the flexible spring blades are secured to various ones of ledges extending to different levels above the bottom of the recess at the opposite wall of the base member from the ledges i2.

The movable contact blade 3 1, in this case the first contact blade, is secured to one of the ledges at the lower level by means of a rivet 35 which extends through the base member and engages a terminal member mounted on the rear face of the base member. In this manner, the contact blade 38 is connected electrically to the terminal member 36. A second contact blade 37] is secured to the adjoining ledge at an upper level by a rivet which passes through the base member to the rear face thereof where it engages one end of a strap member The strap member cs, as shown by Fig. 5, extends across the back face of the base member and is electrically connected at a mid-point to a third contact blade 40 by a rivet is extending through the base member. The contact blade til is placed on one of the lower level ledges immediately adjoining the contact blade 3T1. A terminal member 62 is mounted by means of the rivet ll on the back face of the base member and is in electrical engagement with the strap 39. A fourth contact member 43 is secured to one of the ledges at the upper level by a rivet M which extends through the base member into engagement with the other end of the strap 39. In this manner, the contact blades 37, 40 and 43 are all electrically connected to the terminal member 42. A contact blade 46, in this case the fifth contact blade, is mounted on one of the ledges at a lower level by means of a rivet 4'! which is also a means of securing a terminal member 48 to the back of the switch base. A sixth contact blade 49 is likewise mounted on one of the ledges at an upper level by means of a rivet 50 which extends through the base member, and is connected to one end of a shorting member or strap 5 i The other end of the shorting member is clamped against the terminal member 48 by the rivet 41. In this manner, the contact blades 46 and 59 are both connected electrically to the terminal member 48. As shown by Fig. 5, the opposite ends of the strap member 39 and the rivets 38 and M are placed within recess 45 formed in the back face of the base member in order to insulate the strap from the adjoining terminal members 36 and 48.

Each of the contact blades is provided with a contact surface or button 52 which is adapted to make electrical contact with the contact buttons 32 mounted oneach of the fixed contact members. On those contact blades which are placed at the lower level the contact button faces upwardly toward the top of the recess,-'as shown in Fig. 2, for electrical engagement with the corresponding contact buttons formed on the stationary contact elements which are located at the lower level. On the other hand, the contact buttons on those contact blades which are positioned at the "upper level face downwardly toward the bottom of the recess It for engagement with the corresponding contact buttons 32 formed on the stationary contacts which are located at the upper level. In this manner, the contact blades are located at two different levels, the contact blades 34, Ml and 46- being located at the lower level, and the contact blades 31, 13 and 69 being located at the upper level. Each of the contact blades is provided with a projection lanced from the face of the blade for engagement with a portion of the switch operating mechanism now to be described.

Upstanding from the bottom of the recess ii is an abutment or bearing 5 on which is seated a cam disk formed oi insulating material, and which is secured to a shaft 56 adapted to sup: port an operating handle 57]. The shaft 56 is located in an opening in the cam and extends below the lower face of the cam disk 55 for engagement in an opening (not shown) in the bearing member ti l. The cam member 55 rotates directly upon the bearing 5 as it is rotated by means of the handle 5?. It will be apparent from an examination of Figs. 2 and 3 that the cam disk 55 is located in the space between the two sets or contact blades which are located at the upper and lower levels, and that the cam disk is of a thickness less than the distance between the two levels. The cam is provided with a plurality of depressed portions 53 for engagement with the projections 53 on the various ones of the contact blades. This means that the contact blades are operated or flexed by rotation of the cam in a predetermined sequence to be described later.

By this construction it is possible to provide a switch mechanism of compact form, inasmuch as the contact blades are disposed on each side or the cam disk, and the cam disk occupies the space between the various contact blades which are located on the ledges at difierent levels. In addition, the spring pressure of the contact blades is evenly balanced on each side of the disk, thereby obviating any tendency for the disk to twist or become unseated as it is rotated during opera= tion of the switch.

A positioning means is utilized to determine the various positions of the operating cam. To this end, the cam is provided with an integral sleeve 59, the outer end of which is formed as a polygon, in this case a hexagon 60, corresponding to the number of positions of the switch. However, it should be manifest that the shape of the end of the sleeve may be varied in accordance with the number of operative positions to which the switch mechanism may be turned. A strap 6| is supported on the exterior face of the base member and is provided with an opening (not shown) for receiving the shaft 56, the opening being formed with a flange 63 which engages the end of the sleeve 59 and holds the cam and sleeve seated in position on the bearing 54. Intermediate the strap member SI and the switch base is a cover 64 which may be formed, for example, of sheet fiber, and which is held in position on the base member to close the recess H by the strap member 6|. The sleeve 59 and shaft 56 pass through an opening 64' in the cover. As shown more particularly by Figs. 1 and 2, the strap member is formed of sheet material as a U with the ends 65 of the U resting fiat against the face of the cover member 64 to hold it in position on the base. The ends of the U are secured to the base member by screws 66 which are threaded into openings 61 formed on bosses 68 extending from opposite walls of the base member. The opposite ends of the U-shaped strap 6| are provided with spaced openings 69 formed in the strap at the bends of the U and are adapted to receive the ends of flat spring members 10 disposed in spaced parallel relationship on each side of the polygonally shaped end of the sleeve. The spring members form a positioning means for the switch mechanism, inasmuch as they are flexed outwardly by engagement with the apices of the polyg onally shaped member 60 as the end of the sleeve is rotated from one position to another. The spring members define the various positions of the switch by gripping the opposite flat sides of the polygonally shaped sleeve as shown by Fig. 1. To this end, the spring members are provided with indentations 10' closely gripping the side edges of the sleeve 60.

By the construction described the mounting strap 6| not only provides a support for the positioning mechanism including the spring blades 10 but it also provides a means for holding the switch-operating mechanism including the cam 55 in position due to the fact that the flange 63 bears against the end of the sleeve 59 and maintains the cam seated upon the bearing 54. The strap 6| also holds the cover plate 64 in position to enclose the recess H. In order to mount the switch upon a support the strap 6| may be provided with a plurality of holes (not shown) for engagement by mounting screws.

In one use of the device the switch is utilized to control the heating elements of an electric range. In the showing of Figs. 6 to 11, inclusive, the switch has been connected to a two-part heater system employing two heating units A and B, and the switch is utilized to obtain five different degrees of heat from the heating sys tern. To this end the terminal members 18 and 24 are connected to the outside lines L1--L2, respectively, ofa three wire power supply, for example, a 220 volt system, and the terminal member 3| is connected to the neutral line N of such power supply. The heater system having the two parts A and B is connected electrically to the switch by connecting one end of the element A to the terminal 42 and one end of the element B to the terminal 36. The other ends of both elements A and B forming an intermediate part of the system are connected to the terminal 48.

In the showing of Figs. 6 to 11, inclusive, theterminals and contact blades are shown in a position reversed from the showing of Fig. 3 because the connections are made looking at the rear face of the switch where the terminals are available. Since in the example of the invention described, the switch is designed to operate in six positions, the handle is turned successively clockwise, in the showing of Fig. 3, to the various positions which are approximately 60 degrees apart and which will be indicated by the positioning mechanism comprising the spring strip 10 and the hexagonally-shaped sleeve 60.

In the ofi" position shown by Fig. 6, all of the contact blades are open. By moving the switch handle through an angle of 60 degrees, the switch is placed in the speed position, shown by Fig. '7. In this position the appropriate ones of the cam depressions 56 have been moved to a position beneath the projections on the contact blades 34, 31 and 46 permitting the latter to engage the stationary contacts l3, l4 and 23, respectively. In this position of the switch, current flows from the line L1 through the contact blades 34 and 31 to the ends of each of the heater units A and B, through the intermediate connection to the switch blade 46 and thence to the other line L2. This means that the heater units A and B are connected in parallel between the lines L1 and L2.

In the medium position of the switch, shown by Fig. 8, the contact blades 34 and 46 have been moved to closed position by the depressions in the cam, so that current flows from the line L1 through the contact blade 34 to the unit B of the heating system, through the intermediate connection to the contact blade 46 and thence to the line L2. This means that one part only of the heating system, that is, the heater unit B is connected in parallel between the lines Li and L2.

In the low position of the switch, shown by Fig. 9, the depressed portions 58 of the cam permit the contact blades 34 and 40 to move to closed position so that current flows from the line L1 to the heater unit B, thence to the heater unit A and contact blade 40 to the other line L2. This means that the heater units A and B are connected in series across the power lines L1 and L2.

In the cook position of the switch, shown by Fig. 10, the contact blades 34 and 49 are placed in closed position by means of the operating cam, so that current flows from the line L1 through the contact blade 34, heater unit B, contact blade 49 to the neutral line N. This means that the heater unit B is connected in parallel across-the line L1 and N and, since the voltage across the lines L1N is half of that across the lines L1, L2, the heat derived from the unit B is onefourth that obtained in the medium position of the switch, shown by Fig. 8, in which the unit B is connected across the lines L1, L2.

In the warmfposition of the switch, shown by Fig. 11, the contact blades 34 and 43 are moved to closed position by the cam disk, so that current flows fromv the line L1 through the contact blade 34, heater unit B, heater unit A, contact blade 43, and thence to the neutral line N. This means that the heater units A and B are connected in series across the power lines L1 and N.

While the invention has been described as incorporated in a six-position switch and has been illustrated as controlling an electric range having a two-unit heater system, it will be apparent to one'skilled in the art that the switch may be adapted for controlling other arrangements of heater units by connecting them to the appropriate ones of the switch .blades. Similarly, the

number of contact means may be increased or decreased at will depending upon the uses to which the switch is to be put.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In an electric switch, a body of insulating material having a recess therein, ledges on opposite walls of said recess in stepped relation to one another with the steps being arranged at two diiferent levels, fixed contacts mounted on each ledge at one wall of said recess and having a contact element extending into said recess, flexible spring blades mounted on each ledge at the other wall of said recess, said blades extending across said recess and having contact surfaces adapted to engage said contact elements and a cam disk rotatably mounted in said recess between certain of said blades and engaging said blades for operation thereof, the contacts and blades mounted on the ledges at one level being located on one side of said disk and the contacts and blades mounted on the ledges at the other level being located on the other side of said disk, and means for rotating said disk for controlling a plurality of circuits connected to said fixed contacts and blades.

2. In an electric switch, a body of insulating material having a recess therein, ledges in opposite walls of said recess in stepped relation to one another with the steps being arranged alternate 1y at two different levels, fixed contacts mounted on each ledge at one wall of said recess and having a contact element extending into said recess, flexible spring blades mounted on each ledge at the other Wall of said recess, said blades extending across said recess and having contact surfaces adapted to engage said contact elements, a shaft having a cam disk thereon of insulating material rotatably mounted in said recess between certain of said blades and engaging the latter for operation thereof, the contacts and blades mounted on the ledges at one level being located on one side of said disk and the contacts and blades mounted on the ledges at the other level being located on the other side of said disk, a strap secured to said' body and engaging said disk to hold it in position, and means for rotating said disk for controlling a plurality of circuits connected to said fixed contact and blades.

3. In an electric switch, a body of insulating material having a recess therein, ledges on opposite walls of said recess in stepped relation to one another, the steps being arranged alternately at two diiferent levels, contact elements mounted on each ledge of one wall of said recess, movable contact elements mounted on each ledge at the other wall of said recess, said elements extending across said recess and engaging said firstmentioned contact elements, and a cam disk rotatably mounted Within said recess, and adapted to engage said movable contacts for operation thereof, the fixed and movable contact elements mounted on the ledges at one level being located I on one side of said disk, and the fixed and movable contact elements mounted on the ledges at the other level being located on the other side of said disk, and means for rotating said disk for controlling a plurality of circuits connected to said fixed and movable contact elements.

4. In an electric switch, a body of insulating material having a recess therein, a shaft rotatably mounted within said recess, a cam disk mounted on and rotatable with said shaft and having a projecting sleeve extending beyond the confines of said recess, a plurality of fixed contacts mounted in said recess, a plurality of contact blades cooperating with said fixed contacts and disposed in said recess, some on one side and some on the other side of said cam disk, said cam disk cooperating with said contact blades for operation thereof, a cover for enclosing said recess and a. strap mounted on said body and holding said cover in position, said strap having a portion engaging said sleeve for maintaining said cam disk in position in said recess.

5. In an electric switch, a body of insulating material having a recess therein, a bearing upstanding from the bottom of said recess, a cam element pivotally mounted on said bearing and having a sleeve extending beyond the confines of said recess, a plurality of fixed contacts mounted in said recess, a plurality of contact blades cooperating with said iixed contacts and disposed in said recess some on one side and some on the other side of said cam disk, said cam element cooperating with said contact'blades for operation thereof, a cover enclosing said recess and a strap mounted on said body andholcling said cover in position, said strap having a portion engaging the end or said sleeve for maintaining said cam element in position on said bearing.

6. In an electric switch, a body of insulating material having a recess therein, a cam element rotatably mounted within said recess and having a polygonal-shaped sleeve extending beyond the confines of said recess, a plurality of fixed contacts mounted in said recess, a plurality of movable contact blades cooperating with said fixed contacts and disposed in said recess, some on one side and some on the other side of said cam element, said cam element cooperating with said contact blades for operation thereof, a cover for enclosing said recess, a strap mounted on said body and holding said cover in position, said strap having a portion engaging the end of said sleeve for maintaining said cam element in position in said recess and flat spring strips carried by said strap for engaging opposite sides of said polygonal shaped sleeve.

7. In an electric switch, a body of insulating material having a recess therein, a shaft rotatably mounted in said recess, a cam disk mounted on and rotatable with said shaft and having a polygonal-shaped sleeve extending beyond the confines of said recess, a plurality of fixed contacts mounted in said recess, a plurality of contact blades cooperating with said fixed contacts and disposed in said recess, some on one side and some on the other side of said cam disk, said cam disk cooperating with said contact blades for operation thereof, a cover for enclosing said recess, a U-shaped strap mounted on said body and holding said cover in position, said strap having a portion engaging the end of said sleeve for maintaining said cam disk in position in said recess, fiat spring strips carried by said strap for engaging the sides of said polygonal-shaped sleeve and an operating handle mounted on said shaft.

8. In an electric switch, a body of insulating material having a recess therein, a cam element rotatably mounted within said recess and having a sleeve extending beyond the confines of said recess, a plurality of fixed contacts mounted in said recess, a plurality of flexible spring contact blades cooperating with said fixed contacts and disposed in said recess, each of said flexible contact blades having a projection lanced from the body of the blade for engaging said cam, said cam element being formed with depressions for cooperating with said projections for operating said contact blades, a cover for enclosing said recess and a strap mounted on said body, said strap having a portion engaging the end of said sleeve for maintaining said cam disk in position in said recess.

9. In an electric switch, a body of insulating material, fixed contacts carried by said body, a plurality of contact blades mounted on said body and cooperating with said fixed contacts, rotatable means for operating said blades, said rotatable means being provided with a polygonalshaped sleeve, a U-shaped mounting strap carried by said body portion, said strap being provided with spaced openings at the bends in the U, fiat spring strip elements engaging opposite sides of said polygonal-shaped sleeve, the ends of said flat strips being located in the openings in said strap whereby said strap holds said strip elements in position on said base.

10. In an electric switch, a body of insulating material having a recess therein and a boss upstanding from the bottom of said recess, a plurality of fixed contacts mounted in said recess; a plurality of movable contact blades cooperating with said fixed contacts and mounted in said recess, a cam disk for operating said contact blades pivotally supported on said upstanding abutment and having an extending sleeve, a strap mounted on said body and having a portion engaging the end of said sleeve to hold said cam disk in position for rotation on said abutment, and flat spring members carried by said strap and engaging said sleeve for positioning said cam disk in a plurality of operative positions.

11. In an electric switch, a body of insulating material, opposite walls of the body being provided with contact supporting faces arranged at difierent levels, fixed contacts mounted on each face at one wall of said body, flexible spring contact blades mounted on each face at the other wall of said body, said blades extending across said body and engaging said fixed contacts and a cam disk rotatably mounted on said body between certain of said blades to engage said blades for operation thereof, the blades mounted on the faces at one level being located at one side of said disk and the blades mounted on the faces at the other level being located on the other side of said disk, and means for rotating said disk for controlling a plurality of circuits connected to said fixed contacts and movable blades.

12. In an electric switch, a housing of insulating material having a recess therein, a disklike cam element rotatably mounted in said recess, said cam element having cam surfaces on opposite substantially flat faces, said cam surfaces being spaced radially from the axis of rotation of said cam element, movable contact blades mounted on the walls of the housing forming said recess, fixed contacts mounted on said walls cooperating with said movable contact blades, said movable contact blades extending across said recess in parallel relationship and being disposed on the opposite faces of said cam element, the parallel arrangement of said blades being such that the blades extend outwardly at various distances along a radii on opposite sides of the axis of rotation of said cam element for cooperation with said cam surfaces, and means for rotating said cam element for controlling a plurality of circuits connected to said fixed contacts and blades.

13. In an electric switch, a body of insulating material having walls forming a recess therein, a bearing member integral with said body and upstanding from the bottom of said recess, a fiat cam disk rotatably mounted on said bearing, said disk being provided with cam surfaces on its opposite faces, cooperating fixed contacts and movable contact blades mounted at different levels on opposite walls of said body, said movable contact blades extending across said recess some on one side and some on the other side of said cam disk and cooperating with said cam surfaces for movement into and out of engagement with said fixed contacts, means maintaining said cam element in position on said bearing and a. shaft associated with said cam disk and.

extending beyond the confines of said recess for rotating said disk to control a plurality of circuits through said blades and contacts.

DONALD G. KIMBALL. 

